Gluten

Gluten is an amorphous ergastic protein found combined with starch
in the endosperm of some cereals, notably wheat, rye, and barley. It
constitutes about 80% of the proteins contained in wheat and is composed
of the proteins gliadin and glutenin. Gluten is responsible for the
elasticity of kneaded dough which allows it to be leavened, as well
as the "chewiness" of baked products like bagels.

Extraction

Gluten can be extracted from the flour of wheat and other grains by
washing the starch out. To do this, a simple dough of flour and water
is rinsed with plain water and kneaded until the rinsing water remains
clear and free from starch and bran. For chemical, non-food purposes,
a saline solution provides better results. The remaining lump of gluten
should have a stringy, sticky texture reminiscent of chewing gum.

Usage

Cooked gluten becomes firm to the bite and soaks up a certain amount
of the surrounding broth and its taste. It is therefore commonly used
in vegetarian cuisine, notably Chinese Buddhist, and vegan cuisine where
one variety is called seitan. Some consider it a convincing imitation
meat (particularly duck) when the broth is flavored accordingly.

In the process of baking, gluten is responsible for keeping the fermentation
gases in the dough, allowing it to rise. After baking, the coagulated
gluten ensures that the final product keeps its shape.

Maladies and illnesses caused by gluten

People suffering from celiac disease have an intolerance to gluten
and must go on a gluten-free diet. In their case, the gluten damages
the mucosa of the small intestine, and as a result normal digestion
becomes impossible. After avoiding gluten completely, the intestine
will return to functioning normally.

People with autism and autistic spectrum disorders, like Asperger's
syndrome, may be sensitive to gluten and casein (a protein in milk);
both seem to have an opiate-like effect on these people. The opioid
effect of gluten is caused by gluten exorphines and gliadorphin. These
are peptides formed in the digestion of gluten. See more at gluten-free,
casein-free diet. Another condition which may cause one to follow a
gluten-free diet is dermatitis herpetiformis.

Occurrence

Gluten is found in some cereals (e.g., wheat, rye, barley) and their
end products. No gluten is contained in rice (even glutinous rice),
wild rice, maize (corn), millets, buckwheat, quinoa, or amaranth. Oats
and teff do not contain gluten, but are sometimes grown directly adjacent
to, and/or milled on the same equipment as, other grains that do contain
gluten, and so are commonly contaminated. Non-cereals such as soybeans
and sunflower seeds contain no gluten.

Many people who are unable to digest gluten and thus avoid wheat are
able to digest kamut or spelt.